1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to processing an image signal and displaying an image signal.
2. Description of the Related Art
Recently, various kinds of display devices such as organic electro luminescence (EL) displays, also called organic light emitting diode (OLED) displays, field emission displays (FEDs), liquid crystal displays (LCDs), plasma display panels (PDP) and the like have been developed as display devices substituting for cathode ray tube (CRT) displays.
Among those display devices, the organic EL display is a self light-emitting display device using electroluminescence. The organic EL display, when compared to a display device requiring a separate light source, such as an LCD, is superior in terms of the motion picture characteristic, the viewing angle characteristic, and the color reproduction characteristic, thus attracting much attention, especially as a next-generation display device. The electroluminescence phenomenon refers to a phenomenon in which differential energy is discharged as light when the electronic state of a material (an organic EL device) is changed from a ground state to an excited state by an electric field and the electronic state is returned from an unstable excited state to a stable ground state.
The foregoing display devices generally display an image on a display screen by matrix-type driving. For example, the display device includes several pixels arranged in a matrix form, in which a data line to which a data voltage (a data signal) according to an image signal is applied and a scan line to which a selection voltage (a selection signal; also called as a scan voltage) for selectively applying the data voltage is applied are connected to each of the pixels. The display device displays an image according to the image signal on a display screen by selectively applying the data voltage and the selection voltage to each of the pixels.
In the display device which displays the image on the display screen in a matrix form as described above, the original luminance of the image signal may be degraded in a part of the display screen. This phenomenon may occur due to a voltage drop caused by, for example, an influence of interconnection impedance (electrode impedance) in a line (an electrode) such as a scan line.
In the meantime, techniques which detect a load in each line in a horizontal direction based on an input image signal and correct the image signal based on a result of detection have been developed. Examples of the techniques may include Patent Document 1 and Patent Document 2.    [Patent Document 1] Jpn. Pat. Appln. Laid-Open Publication No. 2008-145880    [Patent Document 2] Jpn. Pat. Appln. Laid-Open Publication No. 2005-62337